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Test Code Miscellaneous Test Specific Gravity, Body Fluid

Reporting Name

Specific Gravity, BF

Useful For

Used to determine concentration of body fluid, to help determine type of body fluid

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Body Fluid

Specimen Required

Collection Container/Tube: Sterile container

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Additional Information: Indicate specimen source. Test is appropriate for all body fluids except urine.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Body Fluid Refrigerated (preferred) 7 days
  Frozen  7 days

Reference Values

No established reference values

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
SGBF Specific Gravity, BF 35414-2


Result ID Test Result Name Result LOINC Value
SG_BF Specific Gravity, Body Fluid 35414-2
FLD4 Fluid Type 14725-6

Method Description

The refractive index of a substance, which is its light-bending power as compared to air, is a physical constant that varies directly with the chemical composition of the substance. Therefore, the specific gravity of a body fluid may be determined from the refractive index of a sample of the fluid. This is accomplished by viewing a drop of the solution through the lens-prism system of the total solids meter (refractometer). Refractometers are temperature-compensated and will read standards correctly only at temperatures between 20° C and 38° C.(Wolf AV: Aqueous Solutions and Body Fluids. Their Concentrative Properties and Conversion Tables. Edited by Hoeber Medical Division. New York, Harper and Row Publishers. 1996, pp 182)

Reject Due To









Method Name